1. Field of the Invention
This invention pertains to artificial body parts which can simulate movement of the body part they replace. More particularly, an artificial finger is envisioned which can simulate movement of a human finger. A plurality of articulated segments are linked together to form a coordinated assembly actuated by a single motivating means, thereby enabling the device to provide human hand-like motion and action.
2. State of the Art
Technology is advancing to the point where creating artificial body parts or limbs goes beyond simply imitating the function of the lost limb. Helping a person to cope with loss of a limb can now be furthered by replacing the limb with one that can also take on the appearance of the original limb.
For example, providing a prosthesis for a person who has lost a hand or arm enables the person to have a substantial portion of the function of the missing limb returned. However, an even greater benefit is obtained when the prosthesis resembles the missing limb, and duplicates the motion and as well as the function.
This invention relates specifically to replacement of an intricate body part, a finger. The intricacy of the motion of the finger is a significant reason why replacing the function often falls short of also duplicating the appearance at the same time. We are forced to wait until techniques of manufacturing and materials used in construction advance to the point where experimentation becomes possible.
While prosthetics is the most obvious advantage of an artificial finger, another advantage comes from providing the function of an artificial finger to robotic devices. In our attempt to humanize technology to make it less intimidating to the average person, it has been proposed that we might succeed by shrouding artificial devices in a cloak of human appearance. A hand created using an assembly of fingers that not only appear human but duplicate the range of motion of human fingers would satisfy this need.
Prior art attempts to create artificial fingers have produced assemblies which suffer from various drawbacks. For example, overall bulk of the finger assembly is typically greater than a human hand. With the added bulk comes weight which requires that the servomotors driving the fingers be powerful, and thus larger and consequently more demanding of energy, and ultimately impractical.
The prior art artificial fingers are also complicated in terms of the number and complexity of parts, reflecting the nature of the part being replaced. For example, devices which rely on pulley systems to control movement have cables that can wear out, fray and break, fall off of pulley wheels, etc.
Accordingly, the challenge in designing an artificial finger assembly, which could replace a substantial portion of the form and function of actual human fingers, comes from designing an assembly that is mechanically simple to build and easy to manipulate without the complexity of prior designs. The fingers should be implemented such that a curling/gripping motion is initiated by actuation of a single lever arm at the base of the finger. Such a design should reduce the size of the fingers as well as the lever arm means for actuating the finger. The design would also be easy to operate.